Imatinib-treated Chronic Myeloid Leukemia Patients Research Articles

Does platelet aggregation differ among chronic myeloid leukemia-chronic phase (CML-CP) patients on tyrosine kinase inhibitors (TKIs)? A tertiary center experience

Abstract Background Tyrosine kinase inhibitors (TKIs) have improved the prognosis of chronic myeloid leukemia (CML) by inhibiting the BCR-ABL kinase. There are concerns regarding the effect of TKI on hemostasis by inhibiting platelet aggregation; the possible reason for this is yet unclear. Objectives To study platelet aggregation response to different agonists [(adenosine diphosphate (ADP), collagen, and arachidonic acid (AA)] using platelet aggregometry in 75 CML-chronic phase (CML-CP) patients on TKI therapy, in complete hematologic response (CHR). Patients and methods This study included 75 CML patients of both sexes of age 32–66 years. A detailed medical history, clinical examination, and platelet aggregation by PAP-4 platelet aggregometer were done for all patients. Results Imatinib-treated CML patients had a lower platelet aggregation response to AA (less than 50% aggregation) than those on nilotinib either first- or second-line treatment, in a statistically significant manner (P=0.001, P=0.025) for both comparisons. But there was no statistically significant difference in platelet aggregation between patients on nilotinib either first- or second-line therapy (P=0.073). Conclusion Platelet aggregation response to collagen and ADP was normal in all CML-CP patients, but it had an impaired response to AA<AQ: Pls check whether the change is appropriate>. Further studies are needed to establish the particular mechanism of this inhibition.

IFNγ directly counteracts imatinib-induced apoptosis of primary human CD34+ CML stem/progenitor cells potentially through the upregulation of multiple key survival factors

ABSTRACT Tyrosine kinase inhibitors (TKIs) have dramatically improved the survival in chronic myeloid leukemia (CML), but residual disease typically persists even after prolonged treatment. Several lines of evidence suggest that TKIs administered to CML patients upregulate interferon γ (IFNγ) production, which may counteract the anti-tumorigenic effects of the therapy. We now show that activated T cell-conditioned medium (TCM) enhanced proliferation and counteracted imatinib-induced apoptosis of CML cells, and addition of a neutralizing anti-IFNγ antibody at least partially inhibited the anti-apoptotic effect. Likewise, recombinant IFNγ also reduced imatinib-induced apoptosis of CML cells. This anti-apoptotic effect of IFNγ was independent of alternative IFNγ signaling pathways, but could be notably diminished by STAT1-knockdown. Furthermore, IFNγ upregulated the expression of several anti-apoptotic proteins, including MCL1, PARP9, and PARP14, both in untreated and imatinib-treated primary human CD34+ CML stem/progenitor cells. Our results suggest that activated T cells in imatinib-treated CML patients can directly rescue CML cells from imatinib-induced apoptosis at least partially through the secretion of IFNγ, which exerts a rapid, STAT1-dependent anti-apoptotic effect potentially through the simultaneous upregulation of several key hematopoietic survival factors. These mechanisms may have a major clinical impact, when targeting residual leukemic stem/progenitor cells in CML.

Assessing the Quality of Life in Imatinib-Treated Chronic Myeloid Leukemia Patients: A Cross Sectional Descriptive Study

Assessing the Quality of Life in Imatinib-Treated Chronic Myeloid Leukemia Patients: A Cross Sectional Descriptive Study

Serotonin re-uptake transporter gene polymorphisms are associated with imatinib-induced diarrhoea in chronic myeloid leukaemia patients

Tyrosine kinase inhibitors (TKIs), the treatment of choice for chronic myeloid leukaemia (CML), can cause lower gastrointestinal (GI) toxicity which is manifested as diarrhoea. The mechanisms are not fully understood. The enteroendocrine signalling compound, serotonin (5-HT), is important for regulating peristaltic motion, fluid secretion and visceral hypersensitivity in the GI tract, and has been implicated in diseases such as irritable bowel syndrome. In this study, we have evaluated whether TKI-induced diarrhoea may be related to variation in the serotonin re-uptake transporter (SERT) gene. CML patients with and without diarrhoea on the SPIRIT2 trial (imatinib, n = 319; and dasatinib, n = 297) were genotyped for the promoter 5-HTTLPR, intron 2 VNTR and rs25531 polymorphisms by PCR-based methods. Diarrhoea was more prevalent in imatinib, than in dasatinib treated patients (P = 0.015), which when stratified by gender was seen to be driven by female patients (P = 0.036). Logistic regression analysis revealed that age, and the dominant HTTLPR with the rs25531 single nucleotide polymorphism (SNP) model, explained the occurrence of diarrhoea in ~10% of imatinib-treated female CML patients. These data suggest SERT polymorphisms influence imatinib-induced diarrhoea but not that of dasatinib.

Distribution of BCR-ABL1 Transcript Variants in Nigerians with Chronic Myeloid Leukemia.

The distribution of BCR-ABL1 transcript variants e13a2 ("b2a2") and e14a2 ("b3a2") in Nigerians with chronic myeloid leukemia (CML) had not been previously studied. In addition, there is paucity of data on the impact of BCR-ABL1 transcript variants on clinical presentation and survival in CML patients in Nigeria. The BCR-ABL1 transcript variants were analyzed in 230 Imatinib-treated CML patients at diagnosis. Patients with incomplete data (n = 28), e19a2 (n = 3) and e1a2 (n = 1) were excluded from analysis of transcript variant on disease presentation and survival leaving only 198. The frequencies of BCR-ABL1 transcript variants were 30 (13.0%), 114 (49.6%), 82 (35.7%), three (1.3%) and one (0.4%) for e13a2, e14a2, co-expression of e13a2/e14a2, e19a2 and e1a2, respectively. A significantly higher platelet count was found in patients with e13a2 variant (531.1 ± 563.4 × 109/L) than in those expressing e14a2 (488.2 ± 560.3 × 109/L) or e13a2/e14a2 (320.7 ± 215.8 × 109/L); p = 0.03. No significant differences were found between the variants with regards to gender, age, phase of disease at diagnosis, total white blood cell count, neutrophil percentage, hematocrit, splenomegaly or hepatomegaly. Overall survival was higher but not statistically significant (p = 0.4) in patients with e14a2 variant (134months) than in e13a2 (119months) and co-expression of e13a2/e14a2 (115months). Nigerian CML patients have the highest incidence of co-expression of e13a2 and e14a2. Distinct disease characteristics which contrast with findings from the Western countries were also identified in Nigerians which may be due to genetic factors.

Validation of the EUTOS Long-Term Survival Score in Chinese Chronic Myeloid Leukemia Patients Treated with Imatinib: A Multicenter Real-World Study.

PurposeTo validate the clinical efficacy of the recently developed EUTOS long-term survival (ELTS) score in a real-world setting.Patients and MethodsA total of 479 chronic myeloid leukemia (CML) patients treated with frontline imatinib between January 2010 and December 2017 were enrolled in this retrospective study. The ELTS score was evaluated on the end-points including complete cytogenetic response (CCyR), progression-free survival (PFS), overall survival (OS) and CML-related death, and the efficiency of the ELTS score was further compared with the historical Sokal, Hasford, EUTOS scores.ResultsWith a median follow-up of 69 months (range, 9–112 months), 462 evaluable patients were stratified into the ELTS low-risk (n = 230), ELTS intermediate-risk (n = 168) and ELTS high-risk (n = 64) groups. For the regular assessment indicators like CCyR, PFS and OS, the ELTS scoring system could effectively identify the corresponding risk groups, similarly with the results provided by previous scoring systems. With respect to the CML-related death, the ELTS score could accurately identify a high-risk group with a significantly higher risk of dying of CML, and the 5-year cumulative incidence occurred in the ELTS high-, intermediate-, and low-risk groups was 11% (95% CI: 3–19%), 5% (95% CI: 1–9%) and 2% (95% CI: 0–4%), respectively. Most notably, the ELTS score outperformed the Sokal, Hasford and EUTOS scores without statistical difference among different risk groups.ConclusionThe ELTS score could effectively predict the prognosis of imatinib-treated CML patients in real-life settings.

BCR-ABL Kinase Domain Mutations Exist in Few Imatinib Treated Chronic Myeloid Leukemia (CML) Patients Exhibiting Stable Cytogenetic and Hematologic Responses

Introduction: Complete hematologic response (CHR) and complete cytogenetic response (CCyR) is observed in almost 80-90% freshly diagnosed chronic phase chronic myeloid leukemia patients treated with Imatinib, a tyrosine kinase inhibitor (TKI). The responses are usually persistent; however the residual disease may be detected molecularly by amplifying BCR-ABL transcript. Furthermore, the leukemogenic potential of the residual BCR-ABL positive cells is reflected when disease reoccurs after discontinuation of therapy. There are evidences of occurrence of mutations in patients who have achieved CCyR, which indicates their role in disease persistence and drug resistance.Patients and Methods: We performed BCR-ABL kinase domain (KD) mutation screening in 150 Imatinib treated CML patients (either resistant or sensitive to therapy) including 84 (56%) individuals manifesting CHR and and 67 (44.7%) with CCyR. For this purpose, nested reverse transcription PCR followed by direct sequence analysis was implemented as previously described. Statistical analysis was performed using SPSS version 19 (IBM, Chicago, IL, USA).Results and Conclusion: Thirty five of 150 patients exhibited mutations in BCR-ABL KD, out of which 11 (31.4%) had achieved CHR and 08 (22.9%) attained CCyR. Single rather than multiple mutated sites in ABL-KD was observed in most of mutant patients achieving CHR (27.3%) or CCyR (27.3%) (Figure 1). Eleven nucleotide substitutions were observed in more than one patient, including Imatinib sensitive individuals with CHR and CCyR (Table 1). Those include C-Helix, SH2 contact, Imatinib binding site (IBS), and A-loop mutations within ABL kinase domain. Overall survival among chronic myeloid leukemia patients achieving different levels of hematologic and cytogenetic response irrespective of mutation status show a favorable survival outcome in those attaining CHR and CCyR (Figure 2). Presence of mutations in cytogenetically stable patients of CML with good hematologic outcomes indicates a likely suboptimal response or TKI resistance during the course of treatment. It is believed by some researchers that mutations do not exist previously, but emerge after Imatinib exposure. Whereas, some believe that TKI's do not induce mutations, rather they select them. Many studies reported a rise in BCR-ABL transcript levels during follow up studies in patients who co-exhibited mutated ABL-KD and CCyR. This suggests that emergence of mutations is a disease evolution process independent of TKI therapy. Studies report that monitoring of nucleotide substitutions in optimally responding patients plays an important role in well managed therapeutic approach. Our studies reveal occurrence of ABL-KD mutations in patints with stable hematologic and cytogenetic response, therefore we suggest for regular mutation screening in CML paients irrespective of their response towards TKIs. DisclosuresNo relevant conflicts of interest to declare.

PDGFRα promoter polymorphisms and expression patterns influence risk of development of imatinib-induced thrombocytopenia in chronic myeloid leukemia: A study from India.

Platelet-derived growth factor receptor has been implicated in many malignant and non-malignant diseases. Platelet-derived growth factor receptor-α is a tyrosine kinase and a side target for imatinib, a revolutionary drug for the treatment of chronic myeloid leukemia that has dramatically improved the survival of chronic myeloid leukemia patients. Given the importance of platelet-derived growth factor receptor in platelet development and its inhibition by imatinib, it was intriguing to analyze the role of platelet-derived growth factor receptor-α in relation to imatinib treatment in the development of imatinib-induced thrombocytopenia in chronic myeloid leukemia patients. We hypothesized that two known functional polymorphisms, +68GA insertion/deletion and -909C/A, in the promoter region of the platelet-derived growth factor receptor-α gene may affect the susceptibility of chronic myeloid leukemia patients receiving imatinib treatment to the development of thrombocytopenia. A case-control study was conducted among a cohort of chronic myeloid leukemia patients admitted to the Lok Nayak Hospital, New Delhi, India. A set of 100 patients of chronic myeloid leukemia in chronic phase and 100 age- and sex-matched healthy controls were studied. After initiation of imatinib treatment, the hematological response of chronic myeloid leukemia patients was monitored regularly for 2 years, in which the development of thrombocytopenia was the primary end point. Platelet-derived growth factor receptor-α promoter polymorphisms +68GA ins/del and -909C/A were studied by allele-specific polymerase chain reaction. Platelet-derived growth factor receptor-α messenger RNA expression was evaluated by quantitative real-time polymerase chain reaction. The messenger RNA expression results were expressed as 2-Δct ± standard deviation. The distribution of +68GA ins/del promoter polymorphism genotypes differed significantly between the thrombocytopenic and non-thrombocytopenic chronic myeloid leukemia patient groups (p < 0.0001). Moreover, +68GA del/del and ins/del genotypes in imatinib-treated chronic myeloid leukemia patients were associated with an increased risk of developing thrombocytopenia, with odds ratios 6.5 (95% confidence interval = 2.02-0.89, p = 0.001) and 6.0 (95% confidence interval = 2.26-15.91, p = 0.0002), respectively. Similarly, -909C/A promoter polymorphism genotype distribution also differed significantly between thrombocytopenic and non-thrombocytopenic chronic myeloid leukemia patient groups (p = 0.02), and a significantly increased risk of imatinib-induced thrombocytopenia was associated with -909C/A polymorphism mutant homozygous (AA) genotypes the odds ratio being 7.7 (95% confidence interval 1.50 to 39.91, p = 0.009). However, no significant risk of imatinib-induced thrombocytopenia was found to be associated with heterozygous genotype (-909C/A) with odds ratio 1.9 (95% confidence interval = 0.86-4.56, p = 1.14). Platelet-derived growth factor receptor-α messenger RNA expression was significantly higher in chronic myeloid leukemia patients compared to controls (p = 0.008). Moreover, patients with imatinib-induced thrombocytopenia had a significantly lower platelet-derived growth factor receptor-α messenger RNA expression, compared to patients without thrombocytopenia (p = 0.01). A differential expression of platelet-derived growth factor receptor-α messenger RNA was observed with respect to different +68 GA ins/del and -909C/A polymorphism genotypes. The +68GA deletion allele and -909A allele were significantly associated with lower expression of platelet-derived growth factor receptor-α messenger RNA. The platelet-derived growth factor receptor-α +68GA del/del, +68GA ins/del, and -909AA genotypes are associated with an increased risk of developing thrombocytopenia in imatinib-treated chronic myeloid leukemia patients. A significantly lower platelet-derived growth factor receptor-α messenger RNA expression accompanies the +68GA deletion allele in an allele dose-dependent manner. Platelet-derived growth factor receptor-α -909AA genotype is also associated with lower expression of platelet-derived growth factor receptor-α. The downregulation of platelet-derived growth factor receptor-α expression may play a causative role in imatinib-induced thrombocytopenia, a common side effect, in the subset of chronic myeloid leukemia patients with platelet-derived growth factor receptor-α +68 GA ins/del, +68 GA del/del, and -909C/A genotypes.

The use of Imatinib resistance mutation analysis to direct therapy in Philadelphia chromosome/BCR-ABL1 positive chronic myeloid leukaemia patients failing Imatinib treatment, in Patan Hospital, Nepal.

Philadelphia chromosome/BCR-ABL1 positive chronic myeloid leukaemia (CML) can be successfully treated with Glivec (Imatinib), which is available free of cost through the Glivec International Patient Assistance programme (GIPAP) to patients with proven CML without means to pay for the drug. We review the acquired mutations in the tyrosine kinase encoded by the BCR-ABL1 gene underlying Glivec failure or resistance in a cohort of 388 imatinib-treated CML patients (149 Female and 239 male) registered between February 2003 and June 2016 in Nepal. Forty-five patients (11 female 34 male) were studied; 18 different BCR-ABL1 mutations were seen in 33 patients. P-loop mutation, Kinase domain and A-loop mutations were seen in 9, 16 and 4 patients respectively. Other mutations were seen in five patients. A T315I mutation was the most common mutation, followed by F359V and M244V. Sixteen mutations showed intermediate activity to complete resistance to Glivec. Among the 45 patients evaluated for BCR-ABL1 mutations, 4 were lost to follow-up, 14 died and 27 are still alive. Among the surviving patients, 16 are receiving Nilotinib, 5 Dasatinib and 3 Ponatinib, while 3 patients were referred to India, one of who received allogenic bone marrow transplantation. Understanding the spectrum of further acquired mutations in BCR-ABL1 may help to choose more specific targeted tyrosine kinase inhibitors that can be provided by GIPAP.

Kinetics of Regulatory T Cells Predict the Recurrence of CML after Stopping Imatinib in Japanese CML Patiens

Introduction: Imatinib have dramatically changed the natural history of chronic myeloid leukemia (CML) leading to significant improvement in clinical outcome and survival rates. Recently, treatment free remission (TFR) is proposed as one of the goals in CML treatment, and some prospective trials suggest that imatinib therapy may be safely stopped in CML patients with deep and sustained molecular responses (Lancet Oncol 2010, Blood 2013, JCO 2014). We have previously show that approximately 70% patients with deep and sustained molecular responses could stop imatinib (ASH 2015). On the other hands, the frequency of regulatory T (Treg) cells in imatinib-treated CML patients with complete molecular response (CMR) exhibited significantly lower compared with that in non-CMR (Haematologica, 2013), indicating the important roles of Tregs in CML treatment. Here, we analyzed T-cell profile in Japanese CML patients to identify biomarkers predicting patients that can successfully stop tyrosine kinase inhibitors (TKI) treatment.Methods: Japanese CML patients treated with imatinib for at least three years and confirmed in deeper molecular response (DMR) for at least two years (>4 log reduction of CML cells by four consecutive PCR tests with imatinib therapy for >24 months) were eligible. Patients who received other TKI or stem cell transplantations were excluded. MR4.5 was tested at the beginning of this study using Ipsogen BCR-ABL1 M-BCR IS-PCR kit in a central laboratory (Sysmex, Kobe, Japan). The patientfs peripheral blood was collected at pre- and 1, 3 months after stopping imatinb. Peripheral blood mononuclear cells (PBMCs) ware subjected to direct staining with T-cell markers and analyzed by flowcytometer.Results: Samples of 68 CML patients (77 patients ware enrolled and nine ware excluded due to consent withdrawal or ineligible) were analyzed. We classified these CML patients into three groups (TFR, Fluctuated and Retreatment groups) by clinical courses after stopping imatinib; TFR group (n=33) maintained MR4.5 without further treatment for 2years, Fluctuated group (n=12) moved below and above MR4.5, Retreatment group (n=23) lost MR4.5 and was re-started TKI retreatment. Frequency of CD4+ T cells and CD8+ T cells in CD3+ T cells ware approximately 60% and 25% in all patients at pre-stopping. FoxP3+ T cells are reportedly classified as three fractions with FoxP3 and CD45RA ; FoxP3loCD45+ naïve Treg (nTreg), FoxP3hiCD45- effector Treg (eTreg) which have highly suppressive function and FoxP3loCD45- effector non-Treg which do not possess suppressive activity (figure 1). Average of the frequency of nTreg, eTreg, and non-Treg fractions in CD4+ T cells were 0.6%, 2.9%, and 3.6% (pre-stopping), 0.7%, 3.5%, and 3.9% (On month after stopping) 0.6%, 2.5%, and 3.4% (3 month after stopping), respectively. The frequency of the each fractions (nTreg, eTreg, non-Treg) and total Foxp3+CD4+ T cells (nTreg+eTreg+non-Treg) elevated 1 month after stopping imatinib, but the frequency of Tregs were suddenly dropped to the basal level at 3 months after stopping imatinib. When the kinetics of T cells were evaluated based on three clinical courses, it is noteworthy that Treg elevation after stopping imatinib was not detected in Retreatment group, indicating that Treg repression by imatinib was not observed in this group (figure 2).Conclusion: Treg population in PBMCs elevated transiently after stopping TKI in CML patients with DMR after long-term TKI therapy. This may due to the release of imatinib suppression to Tregs. However, this transient increase of Tregs was not observed in patients who relapsed after stopping imatinib and received TKI retreatment. Together with our previous reports, it is proposed that activation of anti-CML immune responses by decreasing Tregs by imatinib is an important factor for long duration of anti-CML effect by imatinib. [Display omitted] [Display omitted] DisclosuresTakahashi:Novartis: Honoraria, Research Funding; BMS: Honoraria; Pfizer: Honoraria, Research Funding.

Decreased frequency, but normal functional integrity of mesenchymal stromal cells derived from untreated and Imatinib-treated chronic myeloid leukemia patients

In vitro, Imatinib inhibits the proliferation and stimulates the osteogenic and adipogenic differentiation of mesenchymal stromal cells (MSC). However, it is unknown whether Imatinib affects the biology of MSC in vivo. We asked whether MSC from long-term Imatinib-treated CML patients were affected by the in vivo treatment. MSC from untreated and Imatinib-treated patients displayed normal functional properties (i.e. proliferation, immunophenotype, differentiation and hematopoietic supportive capacity) - but a decreased frequency. In vitro, Imatinib lost its effect when discontinued; which suggest that it has a reversible effect on MSC. Therefore it might lose its effect on MSC after discontinuation in vivo.

Early molecular response in chronic myeloid leukemia patients predicts future response status

Imatinib is the frontline therapy for chronic myeloid leukemia (CML) management. Most of the CML patients achieve major responses, but a proportion (nearly 25-35%) of them develop drug resistance. Molecular monitoring using quantitative real-time PCR at regular intervals according to European LeukemiaNet (ELN) helps in the assessment of long-term outcomes in imatinib-treated CML patients. Eighty-four CML patient samples (42 at diagnosis and 42 at 3-month intervals from the same patients) were analyzed for Bcr-Abl transcript levels. Quantification results revealed that the patients with <10% Bcr-Abl levels at 3 months had higher rates of complete cytogenetic response (CCyR) and optimal responses compared to patients with >10% Bcr-Abl levels (P < 0.0001). Patients with >10% Bcr-Abl levels were found to have 25.0% of suboptimal response and 3.57% of failure to imatinib at standard dose. Hence, the present study confirms that early molecular monitoring at 3 months after imatinib initiation helps in predicting the concurrent cytogenetic response and treatment optimization in CML patients.

Imatinib-Treated CML Patients With Discordant Response Between Cytogenetic and Molecular Tests At 3 and 6 Month Timepoints Have a Reduced Probability Of Subsequent Optimal Response: A Study From The “Gruppo Triveneto LMC”

IntroductionThe 2013 version of the European LeukemiaNet (ELN) recommendations for the management of chronic myeloid leukemia (CML) patients defines as optimal response the achievement of at least a partial cytogenetic response (PCyR) and/or BCR-ABL <=10% at 3 months, and of a complete cytogenetic response (CCyR) and/or BCR-ABL<1% at 6 months. Obtaining less than PCyR (i.e. Ph+ 36-95%) and/or BCR-ABL >10% at 3 months, and less than CCyR and/or BCR-ABL 1-10% at 6 months are regarded as warning. Patiens with discordant response between cytogenetic and molecular tests (e.g. PCyR and BCR-ABL >10% at 3 months) may be alternatively considered at the same timepoint as optimal or warning. Aims and MethodsTo evaluate the outcome of CML patients with discordant results between cytogenetic and molecular tests, we retrospectively analyzed our cohort of early chronic phase CML patients for which both cytogenetic and molecular responses were evaluable at 3 and/or 6 months. All patients received front-line imatinib 400 mg daily. PCyR and CCyR were defined as 1-35% and 0% Ph+ metaphases, respectively; major molecular response (MMR) was defined as BCR-ABL <=0.1%IS. Failure-free survival (FFS) was measured from the start of imatinib to the date of any of the following events: progression to accelerated or blastic phase (ABP), death for any cause at any time, imatinib dose increase (>=600 mg/day) or switch to nilotinib/dasatinib for primary or secondary hematologic or cytogenetic resistance. Cumulative responses and survival probabilities were estimated by the Kaplan-Meier method and compared by log rank test; differences among variables were evaluated by the Fisher's exact test. ResultsA total of 201 patients were analyzed. Median age at diagnosis was 55 (range 20-84) years. The distribution according to the Sokal score was: 86 (42.8%), 79 (39.3%) and 36 (17.9%) patients for low, intermediate and high risk, respectively. We observed that patients with concordant optimal (n=110) and discordant (n=19) results at the 3 month timepoint had significantly different chances of subsequent 6-month CCyR (88% vs 40%, p<.0001) and 12-month MMR (68% vs 12%, p<.0001), while there were no significant differences between patients with discordant or concordant warning (n=21) results (6-month CCyR 40% vs 14% and 12-month MMR 12% vs 0%, respectively). Also, patients with discordant results, compared to concordant optimal patients, had a significantly longer median time to CCyR (10.5 vs 3.5 months, p<.0001) and to MMR (49.6 vs 9.1 months, p<.0001), while there were no differences between discordant and concordant warning patients. Similarly, considering the 6-month timepoint, patients with discordant (n=28) results had a significantly inferior probability of subsequent 12-month MMR compared to concordant optimal (n=104) patients (16% vs 82%, p<.0001) but not different from concordant warning (n=38) cases (7%). Long-term FFS was significantly different between concordant optimal, discordant and concordant warning patients both considering the 3-month (82.8% vs 52.7% vs 9.6%, respectively) and the 6-month (90.4% vs 67.9% vs 23.7%, respectively) timepoints (figure). ConclusionsOur results suggest that only CML patients with concordant cytogenetic and molecular optimal response at the earlier timepoints have an excellent probability of obtaining subsequent MMR and a favourable long-term FFS, while patients with at least one warning result should be carefully monitored, since their risk of treatment failure is higher. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

A Single Nucleotide Polymorphism in cBIM Is Associated with a Slower Achievement of Major Molecular Response in Chronic Myeloid Leukaemia Treated with Imatinib

PurposeBIM is essential for the response to tyrosine-kinase inhibitors (TKI) in chronic myeloid leukaemia (CML) patients. Recently, a deletion polymorphism in intron 2 of the BIM gene was demonstrated to confer an intrinsic TKI resistance in Asian patients. The present study aimed at identifying mutations in the BIM sequence that could lead to imatinib resistance independently of BCR-ABL mutations.Experimental DesignBIM coding sequence analysis was performed in 72 imatinib-treated CML patients from a French population of our centre and in 29 healthy controls (reference population) as a case-control study. Real-time quantitative PCR (RT qPCR) was performed to assess Bim expression in our reference population.ResultsNo mutation with amino-acid change was found in the BIM coding sequence. However, we observed a silent single nucleotide polymorphism (SNP) c465C>T (rs724710). A strong statistical link was found between the presence of the T allele and the high Sokal risk group (p = 0.0065). T allele frequency was higher in non responsive patients than in the reference population (p = 0.0049). Similarly, this T allele was associated with the mutation frequency on the tyrosine kinase domain of BCR-ABL (p<0.001) and the presence of the T allele significantly lengthened the time to achieve a major molecular response (MMR). Finally, the presence of the T allele was related to a decreased basal expression of the Bim mRNA in the circulating mononuclear cells of healthy controls.ConclusionThese results suggest that the analysis of the c465C>T SNP of BIM could be useful for predicting the outcome of imatinib-treated CML patients.

PTCH1 Expression At Diagnosis Reliably Predicts Treatment Failure in Imatinib-Treated Chronic Myeloid Leukaemia Patients

AbstractAbstract ▪875▪This icon denotes a clinically relevant abstractImatinib treatment has radically changed the prognosis of patients with chronic myeloid leukaemia (CML). However, around 23–32% of patients discontinue this therapy due to lack of efficacy, so there is scope to further improve the management of CML patients. We sought to identify a biomarker, or biomarkers that could be used to predict at diagnosis which patients will respond to first line treatment using routinely accessible material.TaqMan Low Density Array (TLDA) technology was used to measure the expression of 29 genes that have been previously implicated in CML pathogenesis, normalized against 3 control genes (GUSB, B2M and 18S). RNA was extracted from archived white cell lysates from the peripheral blood of 73 patients (with appropriate ethical approval), converted to cDNA via first-strand synthesis and these were then analyzed as the learning cohort. ROC curves were plotted in order to find the optimal thresholds for each gene to divide patients into low and high expression groups; in the case of a low area under curve, the median expression value was used. Imatinib failure (IF) was defined as loss of complete hematologic response (CHR) or of complete cytogenetic response (CCyR), progression to advanced phase disease, death or change in treatment from imatinib due to lack of efficacy. Imatinib failure free survival (IFFS), cumulative incidence of CCyR and overall survival related to CML (CML OS) were analyzed by Kaplan-Meier and log-rank test for each gene. Results were validated in an independent cohort composed of 56 patients enrolled in the SPIRIT-1 trial.Of the 29 genes, only PTCH1 (inhibitor of Smoothed (SMO), member of the Hedgehog (Hh) signalling pathway and tumour suppressor gene involved in different cancers) and XIAP (X-linked inhibitor of apoptosis) were significant across multiple endpoints across both cohorts. Using a consistent PTCH1 expression threshold, significant differences in IFFS, CCyR and CML OS were seen, while XIAP predicted only for IFFS and CCyR.In order to corroborate our results, RT-qPCR using a different set of primers and probes (designed in-house) was performed on a subset of 37 patient diagnostic samples from the initial cohort and a further 20 samples taken on treatment, once patients had achieved CCyR, were also analysed for comparison. PTCH1 was successfully validated, and there was good correlation (r=0.823, p<0.001) between both techniques; however, the RT-qPCR results for XIAP did not recapitulate the TLDA data. Low and high PTCH1 expression groups (measured by RT-qPCR) had a 5 year rates of IFFS of 18% vs 94% (p<0.001), CCyR of 46.1% vs 100% (p=0.005) and OS CML 74% vs 100% (p=0.017). Cox regression using PTCH1 expression (categorised into high/low using the ROC), age and Sokal score demonstrated that PTCH1 expression was an independent predictor of IFFS and CCyR, irrespective of the method used for quantification. PTCH1 measurement by RT-qPCR using the second primer-probe set, showed a sensitivity for detecting IF (at any point) of 93.8%, specificity of 81% and negative predictive value of 94.4%. Finally, the median expression of PTCH1 was found to be significantly higher in remission samples compared to those taken at presentation which supports the hypothesis that the distinct PTCH1 signal detected in diagnostic samples reflects the presence of leukemic cells with a reduced expression of this tumour suppressor gene.These results are consistent with current hypotheses regarding Hh signaling and highlight its importance in CML pathogenesis. Given the high negative predictive value of high PTCH1 expression for imatinib failure, we propose that its measurement at diagnosis be used to help identify those patients that may require second generation TKIs or other therapies, which may, in future, include Smoothened inhibitors. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Real-world response monitoring and tolerability of imatinib-treated chronic myeloid leukemia patients captured in a retrospective research registry.

6583 Background: Monitoring tolerability and response to imatinib (IM) is an important aspect of chronic myeloid leukemia (CML) management. The objective of this study is to assess real-world tolerability and response monitoring in IM treated CML patients (pts). Methods: A comprehensive retrospective outcomes research registry of CML pts was created from the University of Utah electronic health record system. Study inclusion was limited to pts diagnosed with CML in chronic phase in 2001 to 2010 and treated with IM as a first-line therapy. Utilization and outcome of cytogenetic and molecular testing within 18 months of IM initiation, rates of adverse drug events (ADEs), and therapy modifications were evaluated by chart review. Results: A total of 92 pts were treated with IM as first-line therapy. Within the first 18 months of treatment, cytogenetic testing was recorded in 45 pts (49%) and of these 33 pts (73%) achieved a complete cytogenetic response (CCyR) in a median of 241 days (range: 110-542); molecular testing was completed in 48 pts (52%) and of these 24 pts (50%) achieved at least a major molecular response (MMR) in a median of 254 days (range: 99-546). Imatinib associated ADEs of any grade (n = 60) occurred in 42 (46%) pts resulting in dose reductions in 15 pts (36%) in a median of 77 days and discontinuation of IM occurred in 9 (21%) pts in a median of 130 days. The IM dose was increased to &gt;400 mg in 21 (23%) pts in a median of 457 days (range: 21-2112). Of pts diagnosed between 2006 to 2010 (n = 34; 37%), 8 (25%) pts transitioned to dasatinib or nilotinib in a median of 397 days (range: 147 to 1057). Reasons for therapy change included physician documented suboptimal response or treatment failure (n = 5) and ADEs to IM (n = 3). Conclusions: Utilization of cytogenetic and molecular testing within 18 months of IM initiation was lower than the National Comprehensive Cancer Network or European LeukemiaNet CML guidelines would suggest. Further research is warranted to understand limited response monitoring and outcomes in non-monitored pts. The ADE rate was similar to clinical trial data. The impact of ADEs on subsequent treatment and outcomes in CML pts deserves further study.

Secondary hyperparathyroidism but stable bone‐mineral density in patients with chronic myeloid leukemia treated with imatinib

Imatinib is currently the standard treatment for chronic myeloid leukemia(CML). Previous studies have shown that imatinib affects bone metabolism in CML patients. However, these effects are not well-studied prospectively. The authors studied bone-mineral density (BMD) and bone metabolism in 17 CML patients and matched controls in 2007 and now repeated the analyses prospectively in 2011. All CML patients were in complete cytogenetic remission during this 4-year period and treated with 400 mg imatinib q.d. (n 5 15) or 600 mg imatinib q.d. (n 5 2). Mean treatment duration was 102 months (range 69–129) in 2011. The authors found that serum levels of parathyroid hormone increased significantly in the patients between 2007 and 2011, and seven out of 17 patients had secondary hyperparathyroidism in 2011. However, the mean areal and volumetric BMDs were stable in the CML patients over the 4-year-observation period. Moreover, the CML patients had significantly higher volumetric BMD in the cortical compartment when compared with controls in 2011 and 2007. Thus, despite a high incidence of secondary hyperparathyroidism,there were no signs of osteoporosis or osteomalacia in imatinib-treated CML patients as suggested earlier.

Discontinuation of imatinib in Japanese patients with chronic myeloid leukemia

It was recently recognized that some chronic myeloid leukemia patients with a complete molecular response could sustain that response after discontinuation of imatinib. To characterize the clinical outcomes and profiles of chronic phase chronic myeloid leukemia patients who could discontinue imatinib, we conducted a nationwide survey in Japan. Among 3,242 imatinib-treated chronic myeloid leukemia patients, we identified 50 who had discontinued imatinib for at least six months; of these we analyzed 43. Molecular recurrence was detected in 19 patients, and a complete molecular response rate was estimated to be 47% following imatinib discontinuation. Based on multivariate regression analysis, imatinib dose intensity and prior interferon-α administration were independently predictive of molecular recurrence within 12 months. The depth of the molecular response should be a factor influencing long-term sustained complete molecular response after discontinuation of imatinib. Additionally, an immunological mechanism modified by interferon-α might control chronic myeloid leukemia stem cells.

Discontinuation of Imatinib in Japanese Patients with Chronic Myeloid Leukemia,

Abstract 3759Imatinib treatment dramatically improves survival in chronic myeloid leukemia (CML) patients, but whether its effects of imatinib can be considered a cure remains controversial. This is because primitive, quiescent, Philadelphia-positive stem cells from patients with CML are insensitive to imatinib in vitro. Nonetheless, it was recently recognized that some patients with a complete molecular response (CMR) could sustain that response after discontinuation of imatinib. In a non-randomized prospective study, Mahon et al. reported that among patients with CMR lasting at least 2 years, CMR was sustained in 41% after discontinuation of imatinib.To characterize the clinical outcomes and profiles of chronic phase CML patients who discontinued imatinib, we conducted a nationwide survey in Japan. Among 3,242 imatinib-treated CML patients, 50 (1.5%) were identified who discontinued imatinib therapy for at least 6 months; of those, 43 were analyzed further. Molecular recurrence was detected in 19 patients, and the complete molecular response (CMR) rate was estimated to be 47% following imatinib discontinuation. Notably, the durations of imatinib therapy and CMR before cessation of therapy were significantly longer, and imatinib dose intensity and the frequency of prior IFN-a administration were significantly higher, in patients sustaining CMR for 12 months after cessation than in those with molecular recurrence. No significant correlations were detected between molecular recurrence and age, sex, Sokal risk, imatinib daily dose, combination with IFN-a, or time to achieve CMR. Moreover, we found a significant difference in estimated CMR rate following discontinuation between patients who had sustained CMR for greater than 24 months prior to imatinib discontinuation and those with less than 24 months (78% vs. 15%, p =0.0002 by Log-rank test, Figure). Based on multivariate regression analysis, only imatinib dose intensity and prior IFN-a administration were independently predictive of molecular recurrence within 12 months (p =0.0035, p =0.0060). The identified prediction formula was: Y= −0.0061 x dose intensity of imatinib(g)-3.17171 x prior IFN-a(Yes=1/No=0) +4.0124. If 1/(1+exp(-1 × Y)) > 0.5, molecular recurrence was predicted; the total accuracy rate of the formula was 82.5%.Although the depth of the molecular response should be a factor influencing long-term sustained CMR after discontinuation of imatinib, other factors, for example an immunological mechanism modified by IFN-a, might control quiescent CML stem cells. To increase the “cure” rate among CML patients, it will be necessary to establish a treatment strategy on the basis of large prospective study of imatinib discontinuation. This should entail the use of a highly sensitive and strict method for monitoring minimal residual disease over the course of a long follow-up period. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Interferon Alpha Treated Patients with Chronic Myeloid Leukemia (CML) In Prolonged Complete Remission Have Increased Numbers of NK-Cells and Clonal Gamma-Delta T-Cells, and a Distinct Plasma Cytokine Profile.

AbstractAbstract 1201 Background.Before the era of tyrosine kinase inhibitors (TKIs), interferon alpha (IFN-α) was the treatment of choice in CML and prolonged survival of responding patients. Recent studies suggest that combination of IFN-α with TKI improves therapy outcome. Significantly, a proportion of IFN-α treated patients in prolonged complete cytogenetic remission (CCyR) have been able to discontinue treatment without disease relapse (Mahon et al. JCO 2002). The mechanism of action of IFN-α therapy is incompletely understood; the drug exerts both direct cytotoxic and immunomodulatory effects on leukemic cells. The aim of this project was to study the immunomodulatory effects of IFN-α in CML patients in prolonged remission and isolate biological markers predicting response. Patients and methods.The study population consisted of CML patients treated with IFN-α monotherapy (n = 10, median therapy time 146 months, range 63–231 months) and CML patients who had discontinued IFN-α therapy but remained in remission for >2 years (n = 9, median therapy time 120 months, range 80–184; median time without therapy 53 months, range 24–96). None of the patients were previously treated with TKI therapy. In addition, non-CML patients (3 patients with essential trombocythemia and one patient with polycythemia vera) treated with IFN-α and healthy volunteers (n = 43) were included as controls. Lymphocyte populations in all four groups were characterized with comprehensive immunophenotyping panels. The clonality of T-cells was analyzed by a TCR γ/δ rearrangement assay by PCR. Lymphocytes were further sorted into CD3+ TCR αβ+ and CD3+ TCR γδ+ populations (n = 8). Additionally, plasma levels of 25 cytokines were measured with a multiplex bead-based cytokine assay (Luminex®). Results.The proportion of NK-cells from lymphocytes was significantly increased in IFN-α discontinued patients (median 26%, range 18–51%) compared to healthy volunteers (11%, 5–21%) or patients on IFN-α therapy (12%, 6–31%)(P=0.0005). Similarly the proportion of CD8+ cells from T-cells was significantly increased in both CML IFN-α groups (55% in IFN-α discontinued patients, 44% in IFN-α treated patients vs. 31% in healthy volunteers; P<0.05 for both groups). Also a larger proportion of T-cells expressed the long-term memory antigen CD45RO in IFN-α patients (74%, 58% vs. 44% in healthy controls, P<0.01). The proportion of regulatory T-cells (CD4+CD25+FoxP3+) was increased in IFN-α groups (6.1%, 5.2% vs. 3.8% in healthy volunteers, P=0.01). Similar changes in immunoprofile were not observed in IFN-treated non-CML patients.Clonal TCR γ/δ rearrangements were observed in 18 of 19 (95%) IFN-treated CML patients as compared to 3 of 22 (14%) in healthy volunteers (P<0.01). In both IFN-α CML patient groups a unique rearrangement pattern was observed: 14/19 (79%) of patients had the Vγ9 gene clonally rearranged. This clonal rearrangement resided in CD3+ γδ+ T-cell population, as assessed by cell sorting. Two of four non-CML patients treated with IFN-α had the same clonal rearrangement, as well as one healthy control (1/22; 5%). Similar clonality patterns have not been observed in dasatinib or imatinib treated CML patients (Kreutzman et al. Blood 2010).IFN-α treatment was associated with a distinct plasma cytokine profile in CML patients. IP-10, IL-6, IL-12, eotaxin, MCP-1, and IFN-γ levels were significantly increased in IFN-α treated CML patients. In particular, eotaxin and MCP-1 levels differed significantly between healthy controls and IFN-α patients who had successfully discontinued IFN-α therapy (428 vs. 1173 pg/ml, P<0.0001 and 107 vs. 459 pg/ml, P=0.0003, respectively). In IFN-α treated non-CML patients, eotaxin or MCP-1 levels were not increased. Conclusions.Our results show that IFN-α treatment induces distinct changes in the immunoprofile of CML patients. Patients who had successfully discontinued IFN-α therapy differed markedly from healthy controls. IFN-α therapy was associated with increased numbers of NK-cells and clonal γδ+ T-cells. These cells possess potent anti-leukemic activity and may contribute to the prolonged therapy responses in this group of patients. Furthermore, plasma cytokine profile could be a helpful biomarker when considering which patients can discontinue the IFN-α treatment without imminent disease relapse. Disclosures:Faber:BMS, Novartis: Consultancy, Honoraria. Porkka:BMS, Novartis: Consultancy, Honoraria, Research Funding. Mustjoki:BMS, Novartis: Honoraria.